I just watched Blaine Bettinger’s video, Sub-Clustering Shared Matches. As I was following the video, I was also trying to do this with my brother’s DNA matches.
The match I started with is listed on my match page as a second cousin. In reality, she is a first cousin once removed. Our common ancestors are Judson Crawford and Josie Hammond.
Her shared match list contained 157 matches. I marked them all with a yellow dot labeled: ICW EB.
When I got to the part about creating Sub-Group 1, I wasn’t sure how to proceed. Other than my brothers, the first match on the list was a first cousin to ICW EB. The next 4 matches are listed as 3rd cousins. They are all known descendants of my great-grandparents.
Unsure on how to proceed, I searched the Facebook group, Genetic Genealogy Tips & Tricks, for the term sub-group. That helped me find the original post on May 1 about the video and this technique. In the comments, I found the answer to my question about using these close cousins to create subgroup 1.
Thus, I skipped my second cousins who I know descend from Judson and Josie Crawford. To create sub-group 1, I started with the first match after these cousins. My brother shares 143 cM with this match and has 27 shared matches with her. These shared matches were marked with an Orange dot labeled, “ICW EB – Sub-group 1”.
For ‘sub-group 2’, I used the next match that does not descend from Judson and Josie Crawford. This match descends from Judson’s father, Washington Marion Crawford. These 32 shared matches were marked with a Green dot labeled, “ICW EB – Sub-group2.”
I skipped another match with Judson and Josie as common ancestors for ‘sub-group 3’. The next match was also a descendant of Washington Marion Crawford. I added these shared matches to Sub-group 2.
The next match is believed to be another descendant of Washington Marion Crawford. Since I haven’t been able to verify the ancestor of this match, I created another subgroup on this match.
I continued working thru these shared matches, creating 11 subgroups. The common ancestors of my ICW match are Judson Crawford and Josie Hammond. Thus, I expected to find subgroups for CRAWFORD, FOSTER, HAMMOND and RALSTON. The subgroups revealed CRAWFORD and FOSTER matches. However, the HAMMOND and/or RALSTON matches are not obvious in these 11 subgroups.
This is an interesting method to study DNA matches.